Distraught over her break-up with Clark, Lana goes to a rogue medical student who experiments with a dangerous kryptonite-based serum that allows people to flat-line but see their dead loved ones. Lana attempts to see her dead parents using the serum and when Clark returns from Honduras to help her, the doctor injects him with the serum and Clark speaks with his dead father...who warns him that Lionel knows his secret. Meanwhile, Lionel continues working to get closer to Martha, and Lex has a near-death vision of his mother.
Elenco: Tom Welling , Erica Durance , Allison Mack , Aaron Ashmore , Annette O'Toole , Callum Blue , Cassidy Freeman , Eric Johnson , James Marsters , Jensen Ackles , John Glover , John Schneider , Justin Hartley , Kristin Kreuk , Laura Vandervoort , Michael Rosenbaum , Sam Witwer , Samuel L. Jones .